The Trump administration has imposed sanctions on 19 Russians for alleged interference in the 2016 presidential election. The U.S. Treasury Department announced the sanctions this morning. This moves comes the same day that the Trump administration issued a joint statement with France, Germany and the U.K. condemning Russia for what has been described as a chemical weapons attack on a former spy on British soil. A senior national security official briefed reporters this morning on the sanctions, including NPR White House correspondent Tamara Keith, who joins us now.

Hi, Tam.

TAMARA KEITH, BYLINE: Hi.

MARTIN: Who exactly is being targeted with these sanctions?

KEITH: Well, it's - this is interesting. These are many of the same people and organizations that were indicted by special counsel Robert Mueller - or were indicted as part of Robert Mueller's investigation into Russian interference in the election. In terms of the organizations, it includes the Internet Research Agency as well as the Russian FSB and GRU. The GRU is one of the - those are both intelligence organizations. And then a bunch of individuals that were involved with the Internet Research Agency...

MARTIN: We should say the Internet Research Agency - that's where the Internet farm was where all the fake news was coming out of in St. Petersburg. Is that right?

KEITH: Yeah. This is the organization that orchestrated much of the meddling in the election, created these false identities online, even created a Twitter account that impersonated a state political party. These are the folks that were involved in sort of the Russian efforts to look like Americans and sow discord in the runup to the presidential election and following it.

MARTIN: So now we have the Trump administration's Treasury Department validating Robert Mueller's investigation, seemingly. Tam, let me ask you, Congress had mandated that the Trump administration issue sanctions on Russia over a month ago, and the White House never signed off on those. Is that what this is? Or is this something in addition?

KEITH: These sanctions come under that congressional act, the America's - Countering America's Adversaries Through Sanctions Act, as well as another executive order. And there's another thing. This isn't just about meddling in the election. They are also targeting Russian individuals that are involved in meddling in other elections, meddling in Ukraine. And also, these officials did mention another Russian effort to target the U.S. energy system.

MARTIN: Is this it? I mean, is this the last that we can see for U.S. response to Russia on this?

KEITH: No. So one official says, this is just one of a series of ongoing actions we're taking to counter Russian aggression; we are all - using all available information to inform future actions, and there will be more to come.